Filtered cigarettes

ABSTRACT

A filtered cigarette in which the inner end of the filter is tapered so that there is a variable drawing resistance along different longitudinal planes of the filter and in which the space between the tobacco and the inner end of the filter provides a chamber in which the tobacco smoke may be cooled; additionally, there is a relatively even draw resistance throughout the entire smoking cycle.

WW States Patent 1 1 1111 3,756,250

Morgenstern 1 Sept. 4, 1973 FILTERED CIGARETTES Primary Examiner-RobertW. Michell l [76] Inventor David Morgenstern, Tel Avlv, lsrae AssistantEjgqmineruGeorge wa Filedi Julie 1972 Attorney- Leonard W. Sherman,Edwin A. Shalloway 21 Appl. No.2 267,975 at [57] ABSTRACT 51 1111. c1.1124c 5/50 A filtered clgareue whlch the Inner end of the filter 58Field of Search 131/103, 10.5 is "WW that W i a variable drawingresistane along dlfierent long1tud1na1 planes: of the filter and 1n 56]References Cited wthiflh tthlet space heitween ltlhe tgibaeco TFdhIEI:intnir end 0 e1erprov1esacamer1nw1c eoacco UNITED STATES PATENTS smokemay be cooled; additionally, there is a relatively 37 1931 even drawresistance throughout the entire smoking cya 3,279,475 10/1966 Brenneret al.... 131/103 1,784,386 Poeck 131/105 2 Claims 11 Drawing Figuressum 1 or 2 PA'TENTEB str 4 m PATENTEDSEP 4197s 3.756250 sum 2 or 2 H6. 9z/0e 4E7 FILTERED CIGARETTES BACKGROUND OF THE INVENTION 1. Field of theInvention This invention relates to filtered cigarettes and filterstherefor and, particularly, to filters allowing air mixing in suchfiltered cigarettes.

2. Description of the Prior Art The increasing death rate resulting fromvascular disorders, lung cancer and cancer of the upper respiratorytract is known to both the medical profession and the general public.While to some extent, it is unquestionable that this increase is due inpart to the overall environmental conditions caused by a highly advancedtechnological society, the results of recent scientific investigationtogether with statistical evidence have shown that there is a connectionbetween smoking and vascular disorders and lung cancer. It is widelyrecognized that the cancer-causing agents or carcinogens are present inthe tobacco tar and nicotine from burning tobacco and that thesecarcinogens are carried to the smokers respiratory tract in the tobaccosmoke.

Many previous attempts have been made to protect smokers against thehealth hazards of smoking, including a variety of mechanical andchemical means for incorporation into cigarettes, cigarette and cigarholders, tobacco pipes and the like with a view to extracting from thetobacco smoke at least a proportion of the harmful substances.

However, most of the previous attempts have failed to take into accounttwo important factors, namely, firstly that tobacco smoke is at a hightemperature by virtue of the combusion temperature (viz. 800C. or more)of the tobacco, and any enveloping material, e.g., cigarette paper(often impregnated with chemical products to sustain burning) and,secondly that the tobacco smoke is low in oxygen, most of the oxygen ofthe air used in the combustion having been converted to carbon monoxideand carbon dioxide. It is apparent that the high temperature and the lowoxygen content of the tobacco smoke entering the mouth, respiratorytract and lungs of a smoker enhance the dangers of or indeed cause theobserved deleterious effect of tobacco smoke. Even those prior artfiltering devices which did combine cooling of the tobacco smoke by airmixing with filtration did not provide the ease of manufacture andeconomy of the filtering device of the present invention.

In the machines presently used in the production of filtered cigarettes1,200 to 2,000 cigarettes are produced each minute, and the expectationis that this rate can be increased to 4,000 cigarettes per minute. The

filter material fed into the machine is of a length calcu- V lated toprovide four or six cigarettes in one operation; the older machinesmaking four and the newer six. In either case, whether four or sixcigarettes are produced in each operation, the process of production isthe same.

To maintain the speed of production it is impossible to incorporateadditional elements, such as the elastic tape in U.S. Pat. No. 3,547,132to Beam or U.S. Pat. No. 3,526,230 to Rosen or the insert member in U.S.Pat. No. 3,602,232 to Grauvogel, et. al.

Furthermore, it would not be possible to use high speed production withthe filter material cut as shown in figure 1 of the Beam patent becausethe elastic tape would alternately point in different directions.

SUMMARY OF THE INVENTION The filtering device of the present inventionovercomes the above objections and difficulities by providing afiltering device having a flow restricting orifice which gives arelatively even mixture of air and smoke throughout the entire smokingcycle, without requiring any manipulation of the filtering device or ofthe cigarette by the smoker. In fact, it is a distinct advantage of thefiltering device of the present invention that a cigarette may beproduced using conventional cigarette manufacturing equipment withoutany significant modifications and at no additional cost to that of aregular filter cigarette, and without affecting the rate of production.

According to one aspect of the present invention, there is provided acigarette having a tobacco section having an upstream end (to be ignitedduring the smoking cycle) and a downstream end; and a tobacco smokefilter in flow communication with the tobacco section. The tobacco smokefilter has an inner end which abuts the downstream end of the tobaccosection and a mouthpiece end. The inner end is tapered or slanted on oneor more surfaces to present one or more surfaces having across-sectional area which is gradually reduced from the point where thetapering or slant begins to a minimum surface area at the inner end. Awrapper connects the tobacco smoke filter and the tobacco section anddefines a mixing chamber disposed between the tobacco section and thetobacco smoke filter. The

tapered surface or surfaces provides a variable drawing resistance alongdifferent longitudinal planes of the filter so that smoke is constrainedto flow first through the plane or planes of least drawing resistance(the plane or planes of shortest length from the mouthpiece end to theinner end) and then, as the shortest plane(s) become saturated with tarand nicotine, progressively through planes of increasing drawresistance, i.e., planes of increasing longitudinal length.

Viewed from another aspect, the invention provides a cigaretteincorporating one or more air ducts in the cigarette wrapper so disposedand formed that, when the smoking means are being used, suction by thesmoker in the usual way causes supplementary air, that is, air that hasnot passed through. the burning portion of the tobacco being smoked tobe drawn through the duct or ducts into an air mixing chamber where thesupplemental air mixes with tobacco smoke and through a tobacco smokefilter into the mouth of the smoker simulataneously with the tobaccosmoke, such supplementary air serving both to lower the temperature ofthe tobacco smoke and to enrich it with oxygen, such tobacco smokefilter providing a variable drawing resistance. Alternatively, an airpermeable wrapper might be used, supplementary air being drawn into theair mixing chamber through the pores of the wrapper.

Conveniently, the variable drawing resistance is provided by having afilter of substantially uniform density, but having an inner endportion, that is, the end furthest from the smokers mouth and closest tothe tobacco end, of reduced cross-section, as compared to the rest ofthe filter. The inner end portion of the filter may carry a steppedsurface or surfaces or a curved surface or surfaces but preferably itcarries a planar slanted surface(s) which tapers from a point or loci ofpoints intermediate the ends of the tobacco smoke filter.

In the production of the filtered cigarettes of the present invention anelongated filter is cut into two or three sections with one or twoknives respectively; the knife or knives are slanted with respect to thelongitudinal axes of the elongated filter. Each of these cut filtersections are inserted into the cigarette wrapping machine betweentobacco sections and is then further cut to produce either four or sixcigarettes in each cycle of production.

It is therefore an object of the present invention to provide a filteredcigarette which will serve to reduce or minimize the dangers arisingfrom smoking tobacco and other combustible materials and which does notnecessitate to any noticeable extent a change in the appearance and sizeof conventional cigarettes, the filtered cigarette being satisfactoryfrom an operative and economical aspect.

It is a further object of the present invention to provide in a filteredcigarette, for the purpose of reducing or minimizing the dangersinherent in smoking, an air mixing chamber for lowering the temperatureof the tobacco smoke and to enrich it with oxygen and a flow restrictivefilter which does not require any effort on the part of the smoker toachieve the flow restricting properties of the filter and which willensure a relatively even mixture of tobacco smoke and supplemental airthroughout the smoking cycle.

It is still a further object of the present invention to provide smokingmeans incorporating in a cigarette having an air mixing chamber in whichsmoke from the burning portion of the tobacco is mixed with supplementalair drawn into the air mixing chamber through one or more ducts, a flowrestrictive filter carrying near its inner end, that is, the endfurthest from the smokers mouth and closest to the tobacco section, asurface or surfaces, each of such surfaces being tapered or slantedwith, respect to the path of flow of the tobacco smoke both before andafter the tobacco smoke is mixed with the supplemental air in the airmixing chamber.

It is a still further object of the present invention to provide in acigarette a conventional cylindrical tobacco smoke filter of uniformdensity carrying near its inner end one or more slanted or taperedsurfaces with respect to the longitudinal axis of the filter, suchtapered surface of the filter defining, along with the tobacco portionand the connecting wrapper of the cigarette, an air mixing chamber inwhich tobacco smoke and supplemental air are mixed prior to impinging oneach tapered or slanted surface or surfaces of the inner end of thefilter, the supplemental air being drawn into such air mixing chamberthrough one or more ducts provided in the connecting wrapper each ductbeing in flow communication between the air mixing chamber and outsideatmosphere or alternatively through an air permeable connecting wrapper.

Still other objectives of the present invention will become apparent inconnection with the following descriptions and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a sectional view of thefiltered cigarette of this invention using the filter shown in FIG. 3.

FIG. 2 shows a sectional view of a different embodiment of the filteredcigarette of this invention using the filter shown in FIG. 4.

FIG. 3 shows a sectional view of one embodiment of a cigarette smokefilter which can be used in the filtered cigarette of this invention.

FIG. 4 shows a sectional view of a second embodiment of a cigarettesmoke filter which can be used in the filtered cigarette of thisinvention.

FIG. 5 shows a sectional view of a different embodiment of the filteredcigarette of FIG. 1.

FIGS. 6, 7 and 8 each show sectional views of other embodiments of atobacco smoke filter which can be used in the filtered cigarette of thisinvention.

FIG. 9 shows the prior art method of cutting cigarette filters.

FIG. 10 shows a method of cutting the cigarette filters of the presentinvention.

FIG. 11 shows an assembly of the filtered cigarettes of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The cigarette of the presentinvention contains in flow communication a tobacco section having anupstream end and a downstream end and a filter element having an innerend abutting the downstream end of the tobacco section, wherein thetobacco smoke filter carries a surface or surfaces near its inner end,each of such surfaces being slanted with respect to the path of flow oftobacco smoke within the cigarette (the path of the tobacco smokegenerally following the longitudinal axis of the cigarette); a spacebetween the tobacco and the. slanted surfacels) defining an air mixingchamber; a wrapper containing the tobacco and filter and furtherdefining the air mixing chamber; and a duct or ducts each in the form ofa hole or aperture leading from the outside of the wrapper into thechamber so that when the cigarette is in use, air is drawn through eachvent and mixes with smoke from the burning tobacco before passingthrough the filter and finally reaching the smokers mouth.

According to a further feature of the invention, an additional filterelement is located adjacent to and at the downstream end of the tobaccosection thereby providing a preliminary filtering action of the tobaccosmoke prior to the mixing of the tobacco smoke and supplementary airdrawn through vents in the wrapper into the air mixing chamber which isdisposed between the additional filter element and the downstream filterelement.

The cigarette 5 shown in FIG. 1 has a wrapper 16 containing tobacco Tand filter F, the filter carrying an inclined surface S near the innerend 11 which abuts the downstream end 9 of the tobacco section T,fomiing air mixing chamber C disposed between tobacco T and filter F.Air vents 8 in the form of radial holes are so located as to place theair mixing chamber C in flow communication with the outside atmosphere,the air vents being provided, for example, by piercing the wrapper l6,eitherbefore or after assembly of cigarette 5. Instead of, or inaddition to, providing air vents in the cigarette wrapper it is alsopossible to use an air permeable cigarette paper through whichsupplemental air may be drawn into the air mixing chamber. The cigaretteis ignited at its upstream end 2 containing tobacco T and the smokerinhales at the mouthpiece end 3 through tobacco smoke filter F.

During the process of smoking the cigarette thus described, as thesmoker draws on the cigarette, smoke is drawn from the point ofcombustion at the upstream end 2 along the tobacco T into the passage orair mixing chamber C while simultaneously supplementary air is drawnthrough one or all of the air vents or perforations 8 into air mixingchamber C where the smoke and supplementary or fresh air are mixed priorto impinging on inclined or tapered surface S of filter F.

The suction required to draw air through the tobacco from the point ofcombustion at 2 to the downstream end of the tobacco 9 depends on theresistance provided by the tobacco which, in turn, for a givencrosssectional area and tobacco density, depends on the length oftobacco through which the air is to be drawn. Similarly, the drawingresistance of the tobacco smoke filter F is also dependent on the lengthof the filter and consequently, the force of suction will be strongest(i.e., least draw resistance) at the shortest longitudinal plane 12-12of the filter Fv Therefore, during the process of smoking the smoke andair from air mixing chamber C will initially be constrained to fiowtowards the narrow end 12 of the tobacco smoke filter F. This narrow endacts as a flow restricting orifice, bringing about the perfect mixtureof smoke with air, highly intensified filtering and ,a relativelyconstant ratio of smoke to air. As the smoking process continues, thenarrow end 12 becomes congested with tars and the fiow of air and smokewill proceed, step by step, along the tapered surface S toward thelongest longitudinal plane 11- 11. The increased draw resistance throughthe filter results in less supplemental air being drawn through thevents into the mixing chamber; this effect is compensated for since thelength of tobacco will have decreased, thereby decreasing its drawresistance. It should be noted however, that the drawing resistance ofthe tobacco section T decreases relatively rapidly and therefore, tomaintain a proper balance of smoke and supplemental air during thesmoking cycle the flow of supplemental air through the filter F must notdecrease as rapidly. This will, to some extent, result naturally, sincethe congested filter will present a greater barrier to the smoke, whichis loaded with tars and nicotine, than to the supplemental air which ismuch thinner. It is thus readily apparent that by proper selection ofthe angle or surface area of the tapered surface S of the tobacco smokefilter F the increased draw resistance through the tobacco smoke filterwill be compensated for by the decreased draw resistance of the tobaccosection, thereby ensuring that the mixture of smoke and fresh air willremain relatively constant throughout the smoking cycle.

FIG. 3 shows the tobacco smoke filter F of the cigarette 5 of FIG. 1.The filter is constructed using conventional cigarette filter material25 and has a relatively uniform density throughout its length. Thefilter can be cut from cylindrical stock and may be provided with awrapper 26. The inner face of the filter, denoted generally atS, istapered from the point 12 located on the outer surface of the filterintermediate the mouthpiece end 3 and the inner end at 11, such taperingextending to the point 11 on the inner end. This tapered surface can beconveniently formed by slicing or cutting a cylindrical filter elementat an angle to the longitudinal axis 28 of the filter element. Thecross-sectional area of the tobacco smoke filter, looking in thedirection of the longitudinal axis 28, is seen to gradually decreasealong planes perpendicular to the longitudinal axis from the point 12 tothe inner end at 11.

Referringnow to FIGS. 10 and 11 the steps for producing the filteredcigarettes of the present invention (using a six cigarette per cyclecigarette wrapping machine) are shown. FIG. 9 shows conventionalcylindrical filters formed from cigarette filter material 25 having arelatively uniform density throughout its length cut into threesections. FIG. 10 shows the method of formation of the preferredembodiment of the filters of the present invention, forming threesections of filter material F1, F2, F3, using tilted cutting edges K.Each of the sections F1,F2, F3, services two cigarettes as shown in FIG.11.

FIG. 11 shows the filter sections F1, F2 and F3 of FIG. 10 disposedbetween tobacco sections T ready to be cut into six cigarettes eachhaving a mixing chamber C. It is thus readily apparent that (accordingto the present invention) the production of filtered cigarettes having atobacco section T, an air mixing chamber C and a tobacco smoke filter Fhaving a slanted inner surface S can be accomplished without making anychanges of equipment and without impairing the speed of production ofcigarette wrapping machines.

FIG. 2 shows a filtered cigarette. as in FIG. 1 with the difference thatthe filter F shown in FIG. 4 is used instead of the filter F shown inFIG. 3.

The filter F of FIG. 4 is tapered at its inner face 30 on the twodiverging surfaces 31 and 32 which intersect each other in a common edge33-33 at or near the longitudinal axis 28 of the filter. The tapering ofeach of the diverging inner surfaces 31 and 32 thus begins at the lociof points 33-33 on or near a plane containing the longitudinal axis andcontinues to the points 34 and 35 respectively on the inner end of thefilter.

The operation of the filtered cigarette in FIG. 2 is substantiallyidentical to the filtered cigarette in FIG. 1 except that the mixture ofsupplemental air and tobacco smoke first impinges the filter at theshortest longitudinal plane through 33-33 and as the narrow end at 33-33of the surfaces of the inner end becomes congested with tars andnicotine, the fiow of air and smoke will proceed, step by step, alongthe tapered surfaces 31 and 32 toward the points 34- and 35 respectivelyon the inner end 30.

Fig. 5 shows a cigarette as in FIG. 1 with the addition of a secondfilter 18 to provide additional filtering action. The insertion of asecond filter as at 18 does not, of course, change the manner ofoperation or the arrangement as shown in FIG. 1. Of course, anadditional filter element can also be similarly placed in the filteredcigarette shown in FIG. 2. FIGS. 6 8 show alternative embodiments of thebasic filter F, each of which may be used in the filtered cigarettesshown in FIGS. 1, 2 or 5. FIG. 6 shows a filter 20 carrying taperedsurfaces 21 and 22 near its inner end whereby the shortest longitudinalplanes are on the outside surface of the filter and the longestlongitudinal plane intermediate the two shortest planes. FIG. 7 shows afilter 23 carrying at its inner end a conical surface 36, with thesummit ending in a point 37. FIG. 8 shows a filter 24 similar tofilter23 except that the pointed end is cut off to provide additional initialsurface area 38. Each of filters 20, 23 and 24 can be used in place offilter F as shown in FIGS. 1 or 5 without modifying the basic concept ofthe present invention.

In addition to the aforementioned advantages, the filters shown in FIGS.3 and 4 will strengthen the walls 19 of the air mixing chamber 10.

The foregoing description is considered as illustrative only of theprinciples of this invention, Other modifications and changes will beapparent to those skilled in the art and is therefore not desired tolimit the invention to the exact construction and operation as shown anddescribed and, accordingly, many modifications and equivalents arecommensurate with the scope of this invention as claimed.

What is claimed is:

l. A filtered cigarette comprising a. a tobacco section of cylindricalconfiguration having an upstream end and a downstream end;

b. a tobacco smoke filter of substantially uniform density having anupstream end and a mouthpiece end which is perpendicular to the flow oftabacco smoke through the filter;

c. a wrapper encircling said tobacco section and said filter, saidwrapper having apertures immediately adjacent said downstream end ofsaid tobacco section and circumferentially arranged about said wrapperthrough 360; the upstream end of said filter being disposed along asingle inclined plane, the forwardmost portion of which is immediatelyadjacent the apertures of said circumferential ring, and rearmostportion of which is significantly displaced from said circumferentialrow of apertures at a point 180 from one of said apertures, the inclinedupstream end of said filter forming with said downstream end of saidtobacco section and said wrapper an air mixing chamber whereby air canbe drawn into said air mixing chamber to mix with the tobacco smoke andtars and nicotine will deposit on said inclined plane progressively fromsaid rearmost portion to said forwardmost portion.

2. A filtered cigarette comprising a. a tobacco section of cylindricalconfiguration having an upstream end and a downstream end;

b. a tobacco smoke filter substantially uniform density having anupstream end and a mouthpiece end which is perpendicular to the flow oftobacco smoke through the filter;

c. an additional cylindrical filter element disposed between saiddownstream end of said tobacco section and said upstream end of saidtobacco smoke filter; and

d. a wrapper encircling said tobacco section and said filter, saidwrapper having apertures disposed between said additional cylindricalfilter element and said upstream end of said tobacco smoke filter andcircumferentially arranged about said wrapper through 360;

said upstream end of said filter being disposed along a single inclinedplane,

the forwardmost portion of which is adjacent the additional cylindricalfilter element and rearmost portion of which is significantly displacedfrom said forwardmost portion at a point approximately 180 from saidforwardmost portion;

said downstream end, said inclined plane, and said wrapper forming anair mixing chamber;

said apertures being substantially completely in flow communicationbetween said air mixing chamber and said outside atmosphere,

whereby air can be drawn into said air mixing chamber to mix with thetobacco smoke, and tars and nicotine will deposit on said inclined planeprogressively from said rearmost portion to said forwardmost portion.

1. A filtered cigarette comprising a. a tobacco section of cylindricalconfiguration having an upstream end and a downstream end; b. a tobaccosmoke filter of substantially uniform density having an upstream end anda mouthpiece end which is perpendicular to the flow of tabacco smokethrough the filter; c. a wrapper encircling said tobacco section andsaid filter, said wrapper having apertures immediately adjacent saiddownstream end of said tobacco section and circumferentially arrangedabout said wrapper through 360*; the upstream end of said filter beingdisposed along a single inclined plane, the forwardmost portion of whichis immediately adjacent the apertures of said circumferential ring, andrearmost portion of which is significantly displaced from saidcircumferential row of apertures at a point 180* from one of saidapertures, the inclined upstream end of said filter forming with saiddownstream end of said tobacco section and said wrapper an air mixingchamber whereby air can be drawn into said air mixing chamber to mixwith the tobacco smoke and tars and nicotine will deposit on saidinclined plane progressively from said rearmost portion to saidforwardmost portion.
 2. A filtered cigarette comprising a. a tobaccosection of cylindrical configuration having an upstream end and adownstream end; b. a tobacco smoke filter substantially uniform densityhaving an upstream end and a mouthpiece end which is perpendicular tothe flow of tobacco smoke through the filter; c. an additionalcylindrical filter element disposed between said downstream end of saidtobacco section and said upstream end of said tobacco smoke filter; andd. a wrapper encircling said tobacco section and said filter, saidwrapper having apertures disposed between said additional cylindricalfilter element and said upstream end of said tobacco smoke filter andcircumferentially arranged about said wrapper through 360*; saidupstream end of said filter being disposed along a single inclinedplane, The forwardmost portion of which is adjacent the additionalcylindrical filter element and rearmost portion of which issignificantly displaced from said forwardmost portion at a pointapproximately 180* from said forwardmost portion; said downstream end,said inclined plane, and said wrapper forming an air mixing chamber;said apertures being substantially completely in flow communicationbetween said air mixing chamber and said outside atmosphere, whereby aircan be drawn into said air mixing chamber to mix with the tobacco smoke,and tars and nicotine will deposit on said inclined plane progressivelyfrom said rearmost portion to said forwardmost portion.